© 2005. All rights reserved.
Black Box Corporation.
Black Box Corporation • 1000 Park Drive • Lawrence, PA 15055-1018 • Tech Support: 724-746-5500 • www.blackbox.com
• e-mail: [email protected]
LOBE ACCESS UNIT
Use a single lobe to accommodate four workstations!
Key Features
Add up to four workstations through a single 4-wire cable.
Expand the capacity of a Token Ring lobe.
Compatible with 4- or
16-Mbps Token Ring.
LEDs monitor active workstations.
No external power supply required.
Support Type 1 or Type
3 Token Ring.
Can operate as standalone units.
L obe Access Units are Token
Ring lobe extenders that quadruple the lobe capacity of a standard Token Ring MAU. They eliminate the need for an additional MAU in situations where extra lobes are needed.
And by using Lobe Access Units to add workstations to the ring in place of extra lobe cabling, you reduce overall design costs.
Connect four workstations to a single lobe with the Lobe Access
Unit. Or, with the flip of a switch, use the Lobe Access Unit as a standalone access unit.
The LT0009A has five ports, each using DB9 connectors. The
MAIN port is female, and the four sub-ports are male. The LT0009A-
UTP also has five ports, but these use RJ-45 connectors. All five ports are female.
To ensure proper operation, you’ll need to use a Relay Tool
(see the Ordering Information section, page 2) during the initial setup.
Specifications
Operating Voltage: 4.5±0.7 volts
Operating Current: 1.0 mA @ 5 VDC
Resistance TX to RX: 4.8±0.2 k
Ω
Insertion Time: 5 seconds
Removal Time: 50 to 200 msec
Return Loss (Minimum): 1–6 MHz:
20 dB; 6–12 MHz: 14 dB;
12–24 MHz: 11 dB
C ommon Mode Rejection
(Minimum): 1–6 MHz: 40 dB;
6–12 MHz: 28 dB;
12–24 MHz: 25 dB
MTBF: 98,398 hours
Speed: 4 or 16 Mbps, autosensing
Compliance: FCC Part A; CE certified; Complies with EMC EN
55022 (1994), EN 50082-1 (1992), and EMC Directive 89/336/EEC
4/1/2005 #19211
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The Lobe Access Unit is small, lightweight, and easy to install.
No strapping adjustments or external power supply are required.
Operating Temperature: 32 to 122°F
(0 to 50°C)
Relative Humidity Tolerance:
10 to 90%, noncondensing
Connectors:
LT0009A: (1) DB9 F, (4) DB9 M;
LT0009A-UTP: (5) RJ-45
Indicators: (4) Red LEDs; lobe activity
Power: From the interface
Size: 7.3"H x 4.5"W x 1.5"D
(18.5 x 11.4 x 3.8 cm)
Weight: 0.8 lb. (0.4 kg)
About Token Ring
Token Ring was developed in the early 1980s by IBM ® . In 1985, the IEEE released document number 802.5, which formally accepted Token Ring as a standard. Although its popularity has been eclipsed by Ethernet,
Token Ring is nonetheless a robust networking standard and is still operating reliably in many legacy networks.
Token Ring is most often used in IBM mainframe environments.
IBM provides Token Ring connections on much of its mainframe computer hardware, and its software enables PCs and mainframes to act as peers on the same network.
The name “Token Ring“ is somewhat misleading. Although its name implies a physical ring shape, Token Ring is actually a star-based topology. Logically, the network operates as a ring—
“tokens“ bearing information are passed from node to node until the token travels completely around the ring.
Token Ring networks are interconnected via passive and active hubs called Multistation
Access Units (MAUs). MAUs are the fail-safe components of Token
Ring networks. If a cable or a connection goes bad, the MAU will drop that node from the ring.
This fail-safe hub arrangement prevents a break from taking down the entire network. Ringin/ring-out ports in each MAU can be used to connect a ring to other rings.
Token Ring repeaters are used to extend distances within a ring.
Repeaters can increase either main-ring or lobe lengths in a
Token Ring LAN. The main-ring length is the distance between
MAUs. The lobe length is the distance from MAU to workstation.
Token Ring cabling
The original Token Ring specifications called for shielded twisted-pair (STP) cable using either a DB9 connector or a unique square connector called the IBM data connector. Later,
Token Ring was adapted to use conventional unshielded twistedpair (UTP) cable with RJ-45 connectors. The most common kinds of Token Ring cabling in use to day are Type 1 and Type 6 STP as well as Type 3 UTP.
Type 1 shielded twisted-pair
(STP) cable is the original wiring for Token Ring. In Type 1 cabling, each wire is constructed of 22
AWG solid copper. Type 1 cable is not as flexible as Type 6 cable and is generally used for long runs in areas where twists and turns are less likely, such as in walls or conduits.
Type 6 Token Ring cable is a lighter, more pliable version of
Type 1 cable. It’s constructed of two stranded 26 AWG copper pairs that are surrounded by an overall braided shield. Type 6 cable is commonly used in offices and open areas, and its flexible construction enables it to negotiate multiple twists and turns.
Type 3 or UTP Token Ring cabling uses the same twistedpair CAT3, CAT5, or CAT5e cabling with RJ-45 connectors as
10BASE-T Ethernet.
Attaching older Type 1 Token
Ring to UTP Token Ring requires a balun or adapter.
Two speeds
Token Ring operates at either
4 or 16 Mbps. While you can mix speeds within one network, each individual ring can operate at just one speed. Simply put, you cannot have 4- and 16-Mbps devices operating in one ring.
Migrating from Token Ring to
Ethernet
Although it’s proven to be reliable and fault-tolerant, Token
Ring has largely been supplanted by Ethernet, and Token Ring network devices are no longer widely available. Additionally,
Ethernet LANs are less expensive to build and operate than Token
Ring, Ethernet can provide far greater bandwidth, and many networking products simply do not support Token Ring at all. The sad reality is that Token Ring is dying. Even IBM has walked away from this standard.
For these reasons, system administrators usually choose to migrate their legacy Token Ring networks to Ethernet by adding new network segments as
Ethernet rather than Token Ring.
There are three different ways to move from Token Ring to
Ethernet by interconnecting the networks. The method you choose depends on whether you’re connecting a LAN or a
WAN and how much you want to spend.
Keep in mind that no matter how you connect the two networks, they both must use the same protocol. In other words, they must speak the same language, such as IP or IPX™.
ITEM
Ordering Information
CODE
Lobe Access Units, 4-Port
DB9 Ports (Type 1)..................................................LT0009A
RJ-45 Ports (Type 3)......................................LT0009A-UTP
You’ll also need...
Relay Tool ..........................................................................LT037
Token Ring Adapter Cables, Type 1...........EVNTRD9-0008
An economical way to combine Novell ® IPX based Token
Ring and Ethernet networks is to have them share a server. Just install either a Token Ring NIC in the Ethernet server or an Ethernet
NIC in the Token Ring server.
Then change the server’s configuration to enable the internal router program. While this method is low cost, it adds traffic and overhead to the server, which can decrease overall network performance.
An easy, standalone hardware solution is to simply use an
Ethernet to Token Ring bridge such as a BLACK BOX ® Ethernet to Token Ring Adapter (LBU9001-
US, LBU9002-US). Just connect the bridge to your Token Ring
MAU and your Ethernet hub and make sure that both networks have the same network identification— in essence, they will become one logical network.
Also, since this is a solution for
LANs, both networks must be close to each other.
Another choice for connecting
Token Ring and Ethernet is to use a router to connect the two networks over a wide-area link.
The router enables each network to maintain its own unique network identifier.
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